1. Field of the Invention
This invention relates to a coupling for joining together lengths of pipes, or, for attaching a fitting to a length of pipe, or, for joining fittings to each other.
2. Description of the Related Art
Couplings of this type are well-known in the art, a typical example being illustrated in Mahoney, U.S. Pat. No. 2,458,714 issued Jan. 11, 1949.
The coupling includes a tubular member which internally houses a sealing ring for cooperation with a pipe exterior, and a locking groove for the reception of a locking member, typically, a length of ductile wire or a coil spring which is inserted tangentially through an opening in the wall of the tubular member, and which extends between a groove formed in the tubular member and a juxtaposed groove formed in the outer periphery of the pipe. Thus the coupling includes the tubular member in combination with the locking member.
One disadvantage of such couplings is that the tubular member must first be assembled onto the pipe. The locking member must then be inserted tangentially through the aperture in the wall of the tubular member, and then pushed into encircling relation with the pipe periphery. The locking member is in this manner properly positioned within the internal groove in the tubular member and the external groove in the pipe periphery in bridging relationship therewith.
As will be readily apparent, the locking member can only be inserted tangentially into the tubular member at the time the groove in the interior of the tubular member and the exterior of the pipe periphery are in correct position of axial alignment. This, in turn, demands an extremely close tolerance in the positioning of the pipe and tubular member axially relative to each other for their respective grooves to be in axial alignment with each other. Commonly, a radial abutment is provided on the exterior of the pipe periphery, as taught by Mahoney in U.S. Pat. No. 2,458,714. More conveniently, the abutment can be provided internally of the tubular member as a shoulder that is engaged by the pipe end when the tubular member is correctly positioned over the pipe end.
It is known in the art to provide a locking member for such a coupling that can be withdrawn from the tubular member in the event that it is desired to disassemble the coupling from the pipe. This is done by pulling the locking member circumferentially out of the tubular member by grasping a free end of the locking member that extends out of the tangential opening in the tubular member. There still remains the problem that to secure the tubular member to the pipe, the member must be correctly assembled onto the end of the pipe, and then, and this possibly in a most inconvenient location, the retainer inserted into the tubular member and then forced circumferentially within the coupling into encircling relation with the pipe groove.